OBJECTIVETo understand the occurrence and development of adolescent students' type 2 diabetes mellitus (T2DM) by researching the characteristics of the adolescent students' impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) effected by overweight or obesity.

METHODSFrom May to November 2007, 3856 middle school students aged 11 to 18 years old in Dongguan city were enrolled in the study. Overweight or obesity (b/Ob) depended on three indexes: the national unified school-age children and adolescent students' body mass index (BMI) and the temporary screening classification standard II established by the Working Group on Obesity in China, BP > or = 140/90 mm Hg (1mm Hg = 0.133 kPa) and fasting capillary whole glucose which was greater than or equal to 5.6 mmol/L. The fasting capillary whole glucose was screened by blood glucose meter from fingertips. Students who had any abnormal indexes were brought into this study. On basis of voluntary principle, blood lipid, fasting blood glucose (FPG) and 2-hour postprandial blood glucose (2 h PG), fasting insulin (FIns) of 368 male and 326 female students who conformed to these conditions were measured using their venous blood. By temporary BMI standard II, they were divided into overweight group (b) and obesity group (Ob). Data of different age groups (11 to 14; 15 to 18 years old) was analyzed.

RESULTSThe BMI, low density lipoprotein cholesterol (LDL-C), insulin resistance index (IR), IFG and IGT of the same age stage in two groups were compared. The BMI value was (22.1 +/- 2.4) kg/m2, LDL-C was (2.38 +/- 0.65) mmol/L, IR was 1.15 +/- 0.58 and the detection rates of IFG and IGT were 3.5% and 1.4% respectively in female students aged 11 to 14 years old in b group. In Ob group, BMI value was (24.4 +/- 3.9) kg/m2, LDL-C was (2.70 +/- 0.73) mmol/L, IR was 1.36 +/- 0.67 and the detection rates of IFG and IGT were 14.6% and 6.3% respectively. t or chi2 values of two groups which were compared were 4.83, 2.45, 2.10, 7.41 and 7.99 (P < 0.01 or P < 0.05). BMI value was (25.8 +/- 3.1) kg/m2, LDL-C was (2.35 +/- 0.62) mmol/L, IR was 1.14 +/- 0.64 and the detection rates of IFG and IGT were 3.1% and 4.1% respectively in 15 to 18 years old in b group. In Ob group, BMI value was (28.0 +/- 4.3) kg/m2, LDL-C was (2.69 +/- 0.69) mmol/L, IR was 1.43 +/- 0.84 and the detection rates of IFG and IGT were 12.8% and 15.4% respectively. t or chi2 values of two groups which were compared were 3.33, 2.79, 1.87, 4.75 and 5.17 (P < 0.01 or P < 0.05). BMI value was (22.4 +/- 2.3) kg/m2, LDL-C was (2.36 +/- 0.67) mmol/L, IR was 1.19 +/- 0.65 and the detection rates of IFG and IGT were 3.6% and 1.8% respectively in male students of 11 to 14 years old in b group. In Ob group, BMI value was (24.6 +/- 4.2) kg/m2, LDL-C was (2.68 +/- 0.71) mmol/L, IR was 1.44 +/- 0.89 and the detection rates of IFG and IGT were 13.3% and 9.4% respectively. t or chi2 values of two groups which were compared were 4.85, 2.72, 2.19, 6.75 and 6.76 (P < 0.01 or P < 0.05). BMI value was (26.4 +/- 2.8) kg/m2, LDL-C was (2.35 +/- 0.70) mmol/L, IR was 1.24 +/- 0.68 and the detection rates of IFG and IGT were 4.7% and 5.6% respectively in 15 to 18 years old in b group. In Ob group, BMI value was (28.2 +/- 4.8) kg/m2, LDL-C was (2.71 +/- 0.73) mmol/L, IR was 1.50 +/- 0.95 and the detection rates of IFG and IGT were 17.9% and 17.9% respectively. t or chi2 values of two groups which were compared were 2.80, 2.69, 1.84, 6.68 and 6.27 (P < 0.01 or P < 0.05). The male students' FPG of 11 to 14 years old in b group was (4.88 +/- 0.76) mmol/L and FPG of Ob group was (5.09 +/- 0.80) mmol/L. Two groups were compared and t = 1.84 (P < 0.05). The statistical differences were all observed. We compared different age stages and found that the male students' 2-hour PG of 11 to 14 years old in Ob group was (5.13 +/- 1.18) mmol/L and the 2-hour PG of 15 to 18 years old was (5.36 +/- 1.24) mmol/L. Two groups were compared and t = 1.78 (P < 0.05) near the adults value. Male students' IGT of 11 to 14 years old (b/Ob) had 8 positive cases and the positive detection rate was 3.6%. IGT of 15 to 18 years old (b/Ob) had 13 positive cases and the positive detection rate was 8.9%. Two age stages were compared and chi2 = 6.86 (P < 0.01). Female students' IGT of 11 to 14 years old (b/Ob) had 5 positive cases and the positive detection rate was 2.6%. IGT of 15 to 18 years old (b/Ob) had 10 positive cases and the positive detection rate was 7.4%. Two age stages were compared and chi2 = 4.02 (P < 0.05). All had statistical significance. The high IGT incidence rate of b/Ob group's male and female students was in the stage of 15 - 18 years old. Male students were more obvious.

CONCLUSIONT2DM prevention among adolescent students should start with body overweight control. Meanwhile, the adolescent students with high risk factors should be screened regularly and early measures should be taken to prevent the impaired glucose regulation (IFG, IGT) transforming into T2DM.